CSS Sprites研究

1、What is CSS Sprites

CSS sprites allow you to create a single file that contains all the images laid out in a grid, meaning only a single image and only a single server call, with roughly the same file size because the empty space is compressed. In that file, you will place all individual “sprites” that make up your interface separated by enough space that they don’t start running over each other. You’ll then set the background position (using negative values to move the background up) and include enough space around each sprite so that only it appears in the background of the element, effectively masking the rest of the sprite images